Nosocomial infection studies have shown that the use of FFP3 respirators at Addenbrooke Hospital “may reduce ward infections to zero”

First published on Tuesday, June 29, 2021 02.48 EDT

Studies have shown that an NHS hospital upgraded the type of masks used by staff in the Covid-19 ward, and the results showed that the coronavirus infection rate for these staff in the hospital dropped sharply by 100%.

The Addenbrooke Hospital in Cambridge upgraded the mask from a liquid-proof surgical mask (FRSM) to a filter face mask 3 (FFP3) respirator and made changes in late December based on its own staff test data.

Until recently, Public Health England (PHE) also recommended that healthcare workers caring for Covid-19 patients should use FRSM as respiratory protective equipment.

PHE recommends that if you are performing an aerosol-generating procedure, such as inserting a breathing tube into the patient’s trachea, you should use an FFP3 respirator.

The guidelines have recently been updated, requiring NHS organizations to assess the risks of Covid-19 to employees and provide FFP3 respirators where appropriate.

Since the beginning of the pandemic, Addenbrooke's has been testing employees for Covid-19, even if they do not show any symptoms.

Tests have shown that even with recommended respiratory protection equipment, medical staff caring for Covid-19 patients are at a greater risk of infection than staff in non-Covid wards. In response, the hospital's infection control committee upgraded the types of masks used by employees in Covid-19 wards.

After changing the protective equipment, the incidence of infection in the two types of wards was similar.

The study has not been peer-reviewed, but due to the urgent need to share information related to the pandemic, it was released in advance.

Dr. Chris Illingworth of the MRC Department of Biostatistics at the University of Cambridge said: "Once the FFP3 respirator was introduced, the number of cases attributed to Covid-19 exposure in the ward dropped sharply-in fact, our model suggests that the FFP3 respirator may have cut the ward. -Zero based on infection."

Experts warned that even after vaccinations, Covid cases acquired by hospitals may continue to pose a challenge, so they called for better personal protective equipment. A previous study found that in April this year, medical staff in three hospitals in India were The Delta variant broke out within. In 1999, although many of them received two Covid jabs.

This study, which has been released as a preprint, shows that in a hospital, 30 of the 3,800 employees were infected with the new coronavirus and developed symptoms, most of which involved Delta variants — 11 were clearly related to a “super” . Communicator" event.

In the second hospital, out of 4,000 medical staff, 118 were symptomatically infected; in the third hospital, out of 1,100 medical staff, 70 were symptomatically infected. Likewise, most people affected have Delta variants.

The team added that clusters of more than two infected individuals were found only in the Delta variant.

The co-author of the study, Professor Ravi Gupta of the University of Cambridge, said: "The data we provide is basically consistent with people who have been vaccinated and then transmitted [infection] to others."

He added: “While the vaccine will protect healthy people in the community from serious illnesses, the Delta variant increases the likelihood of serious illnesses in hospital environments with vulnerable patients.”

The team stated that their findings emphasize the need to continue infection control measures in the post-vaccination era.

Dr. David Strain, a senior clinical lecturer at the University of Exeter School of Medicine, agreed. He pointed out that although more and more data show that vaccination can protect people from Covid, including serious diseases, this new work emphasizes There is still a risk of carrying and spreading Delta variants in vaccinated individuals.

"This is especially important for health care workers who have a higher rate of contact with virus patients, and also have a higher probability of contact with extremely vulnerable people, while the 90% protection provided by the vaccine still puts them at risk," he said. Say.

"In addition, there is evidence that people who are fully vaccinated can now infect and spread the virus. Although they will not get sick, we need to be vigilant about whether this puts people at long-term Covid risk."

Saffron Cordery, deputy chief executive officer of NHS Providers, said the survey results remind us that there is no room for complacency.

"As we have seen, vaccines are breaking the link between Covid-19 infection, hospital admission and death. That is why it is so important for as many eligible people as possible to accept them," she said.

"But they are not a panacea. Trust leaders to recognize the continuing importance of strict infection control, effective personal protective equipment and social distancing in combating the spread of Covid-19."